Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 05-15-09, 04:00 PM   #1
FlatMaster
Genius
Thread Starter
 
FlatMaster's Avatar
 
Join Date: Jan 2008
Location: Auburn, AL
Bikes: Specilized Sirrus
Posts: 324
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Removing square taper cranks with damaged threads

Unfortunately, the threads on my drive side cranks are damaged. I'm looking for some other way to remove the cranks. I know that with skill and the right tools, I could file off the first few threads. However, I don't think I have the skill for this. THis is my idea.

Could one loosen the cup and lockring on the non-drive side as far as possible, then strike the spindle with a hammer? The fixed cup on the drive side would push the crank off of the spindle.

Any other ideas for removal of a crank with damaged threads? The crankset is being replaced with a sealed bottom bracket, so destructive removal is a possibility.
FlatMaster is offline   Reply With Quote
Old 05-15-09, 05:09 PM   #2
Al Criner
Senior Member
 
Join Date: Aug 2007
Location: NorCal
Bikes: 2009 Surly Cross Check Frankenbike
Posts: 545
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
A gear puller from a auto parts store will pull them off.
Al Criner is offline   Reply With Quote
Old 05-15-09, 05:33 PM   #3
FlatMaster
Genius
Thread Starter
 
FlatMaster's Avatar
 
Join Date: Jan 2008
Location: Auburn, AL
Bikes: Specilized Sirrus
Posts: 324
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Never seen one of thoes. Might get one just to own another cool tool.
FlatMaster is offline   Reply With Quote
Old 05-15-09, 06:05 PM   #4
HillRider 
Senior Member
 
Join Date: Aug 2005
Location: Pittsburgh, PA
Bikes: '''96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '12 Surly Pacer, All are 3x8,9 or 10. It is hilly around here!
Posts: 29,117
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 179 Post(s)
Heat. Apply a torch or heat gun to the crank and then try to knock it off from the back using a heavy dowel or large diameter rod. Don't overdo it. You want to expand the crank, not melt it.
HillRider is offline   Reply With Quote
Old 05-15-09, 06:53 PM   #5
operator
cab horn
 
Join Date: Jun 2004
Location: Toronto
Bikes: 1987 Bianchi Campione
Posts: 28,306
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by FlatMaster View Post
Unfortunately, the threads on my drive side cranks are damaged. I'm looking for some other way to remove the cranks. I know that with skill and the right tools, I could file off the first few threads. However, I don't think I have the skill for this. THis is my idea.

Could one loosen the cup and lockring on the non-drive side as far as possible, then strike the spindle with a hammer? The fixed cup on the drive side would push the crank off of the spindle.

Any other ideas for removal of a crank with damaged threads? The crankset is being replaced with a sealed bottom bracket, so destructive removal is a possibility.
You have 3 options

1) Take it to a LBS with a wedge tool
2) Automotive puller
3) Grinder the crankarm in half

When you say the crankset is being replaced with a sealed bb, you didn't actually tell us if destructive removal of the crankset itself is acceptable or not. The BB can always be replaced if the crankarm extractor threads are damaged if you don't care about the crank itself.
operator is offline   Reply With Quote
Old 05-16-09, 01:13 AM   #6
sunburst
Senior Member
 
sunburst's Avatar
 
Join Date: Jan 2008
Location: NorCal - bay area
Bikes: giant, trek, peugeots, friday
Posts: 1,320
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Here's what I did:
interesting tip for stuck cranks

There were people who disagreed with the approach (and most on this forum know more than me!), but it worked. It only took a couple of tries also, and not much heat.
sunburst is offline   Reply With Quote
Old 05-16-09, 04:58 AM   #7
griftereck
Senior Member
 
Join Date: Jun 2008
Location: angus scotland
Bikes: Grifter BSA 20
Posts: 600
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I use a cold chisel and a hammer to hit the back of the crank arm at the centre beside the axle.
it ussualy takes a couple of taps to pop the arm off.
griftereck is offline   Reply With Quote
Old 05-16-09, 05:56 AM   #8
I_bRAD
Call me The Breeze
 
I_bRAD's Avatar
 
Join Date: Aug 2006
Location: Corbyville Ontario
Bikes: 2004 Litespeed Siena, 1996 Litespeed Obed, 1992 Miele (unknown model), 1982 Meile Uno LS.
Posts: 3,699
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by FlatMaster View Post
Could one loosen the cup and lockring on the non-drive side as far as possible, then strike the spindle with a hammer? The fixed cup on the drive side would push the crank off of the spindle.
Interesting idea. I'd remove the NDS cup entirely and be sure to properly support the BB shell before you get the hammer out.
I_bRAD is offline   Reply With Quote
Old 05-16-09, 06:21 AM   #9
JohnDThompson 
Old fart
 
JohnDThompson's Avatar
 
Join Date: Nov 2004
Location: Appleton WI
Bikes: Several, mostly not name brands.
Posts: 16,780
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 219 Post(s)
If the threads aren't too badly damaged, you can clean them up with one of these:

JohnDThompson is online now   Reply With Quote
Old 05-16-09, 06:40 AM   #10
EatMyA**
Senior Member
 
EatMyA**'s Avatar
 
Join Date: Dec 2006
Location: Southern California
Bikes:
Posts: 930
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
crowbar
EatMyA** is offline   Reply With Quote
Old 05-16-09, 06:41 AM   #11
mmmdonuts
Gluteus Enormus
 
mmmdonuts's Avatar
 
Join Date: Dec 2007
Location: Raleigh, NC
Bikes: Yes
Posts: 2,244
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Remove the chainrings, unless you like scars.
Apply heat to the crankarm spider just around the spindle area.
Use 5/8 or bigger open ended wrench to pry it off from behind the crankarm. Between the back of the crank and the BB cup face. This is assuming you can fit the wrench back there.
mmmdonuts is offline   Reply With Quote
Old 05-16-09, 06:52 AM   #12
curbtender
Senior Member
 
curbtender's Avatar
 
Join Date: Mar 2007
Location: SF Bay Area, East bay
Bikes: Marinoni, Kestral 200 2002 Trek 5200, KHS Flite, Koga Miyata, Schwinn Spitfire 5, Schwinn Speedster, Mondia Special, Univega Alpina
Posts: 3,996
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 57 Post(s)
If the bike isn't too far dismanteled you can try riding around with the keeper bolt removed and see if that loosens it up.
curbtender is offline   Reply With Quote
Old 05-16-09, 03:47 PM   #13
Sturmcrow
Senior Member
 
Join Date: Mar 2006
Bikes:
Posts: 349
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
When I was a kid and had never heard of a crank puller I used to just bash away at the crank with a hammer until it fell off. Sure it got marred, but I pulled that crank several times and it never broke.

Hopefully it broke later while the SOB that stole it was riding!
Sturmcrow is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 03:12 PM.